1. Technical Field
The present invention relates to a liquid ejecting head which ejects liquid from nozzle orifices, a manufacturing method of the liquid ejecting head, and a liquid ejecting apparatus.
2. Related Art
Among liquid ejecting heads which eject liquid, there is known an ink jet type recording head, in which piezoelectric elements are provided on one face side of a flow path forming substrate, in which pressure generation chambers that are communicated with nozzle orifices are provided, and ink droplets are discharged from the nozzle orifice by making a pressure change occur in the pressure generation chamber in accordance with displacement of the piezoelectric element.
As the ink jet type recording head, there is proposed a recording head configured such that a protective substrate is joined on the piezoelectric element side of a flow path forming substrate, each terminal of a driving circuit provided on the protective substrate is electrically connected to each piezoelectric element by a bonding wire by using wire bonding, and a driving signal from the driving circuit is supplied to the piezoelectric element through the bonding wire (refer to, for example, JP-A-2005-053079, JP-A-2007-301736, and JP-A-2008-023799).
Also, as the ink jet type recording head, there is proposed a recording head, in which a COF substrate which supplies a driving signal is connected to a plurality of piezoelectric elements (refer to, for example, JP-A-2006-281477).
However, if each terminal of the driving circuit is individually connected to each piezoelectric element by wire bonding, the wire bonding must be carried out for as many as the number of piezoelectric elements, so that there is a problem in that manufacturing time and costs increase.
Also, a region for disposing the terminal, to which the bonding wire is connected, needs to be provided at the piezoelectric element, so that there is a problem that the head increases in size.
In addition, as in JP-A-2007-301736, there is also proposed a recording head, in which a piezoelectric element is electrically connected by using a COF substrate. However, in a case where a row of the piezoelectric elements arranged in parallel is provided in plural rows, there is a problem in that the resin material, such as an anisotropic electrically-conductive adhesive or a potting agent, which is used for the connection of the COF substrate and the piezoelectric elements, flows out in between the rows of the piezoelectric elements, so that there is fear that electrical conduction defects may occur. In addition, if the distance between the rows of piezoelectric elements is widened in order to suppress electrical conduction defects due to the overflowing resin, head increases in size.
Also, such a problem exists not only for ink jet type recording heads, but also for liquid ejecting heads ejecting liquid other than ink.